There are today many manufacturing processes which require operations such as bending, machining, drilling, painting, etc. to be performed on heavy workpieces such as steel plates, structured channels, beams and the like. Often, the workpiece must be placed in a specific precise position for each operation to be performed, necessitating the workpiece to be turned while suspended in a variety of directions about horizontal and vertical axis. Since these workpieces are too heavy to be supported by human strength while being manipulated, apparatuses have been devised to provide the necessary support and at the same time enable such manipulation. Examples of such apparatuses are in the immediately following discussion.
U.S. Pat. No. 2,860,002 to Herbst discloses a hoisting apparatus which attaches to the workpiece, i.e. a die set, to be supported via lifting plates having keyhole slots therein which engage with mating studs which are integral parts of the workpiece. The device of Herbst would be useless for any workpiece that does not possess the necessary mating studs. Furthermore, the device of Herbst does not enable locking the workpiece in a fixed position with respect to the horizontal, nor does it suggest rotation about a vertical axis.
U.S. Pat. No. 3,161,431 to Francis discloses a device for carrying bricks which features a rotating platform for the bricks permanently attached to a frame which supports the platform. The device of Francis is not designed for work to be performed on the rotating platform itself, nor could the device be so used, except for the one platform in the original construction, in view of the permanent attachment. The device of Francis, therefore, is not relevant to the manipulation of heavy workpieces.
Other references even less relevant to the present invention, but mentioned herein to further set forth the extent of the prior art are the following: U.S. Pat. No. 2,966,380 to Swenson; U.S. Pat. No. 3,197,249 to Garman; U.S. Pat. No. 3,253,851 to Gilbert; U.S. Pat. No. 3,297,353 to Carlson; U.S. Pat. No. 3,456,976 to Husmann; and U.S. Pat. No. 3,927,909 to Hack.
In contradistinction to the devices of the prior art, the present invention comprises a unique apparatus which may easily be attached or detached from a workpiece, with the workpiece not requiring parts the sole purpose of which are to mate with the apparatus, and which enables the workpiece to be handled and turned over or rotated until all work is completed thereon.